Today, one or more radar systems are often used in vehicles in order to detect obstacles in the surroundings. Such a radar system is arranged to distinguish or resolve single targets from the surroundings by using a Doppler effect in a previously well-known manner. Preferably, such a radar system is arranged to provide resolution in all three dimensions by performing two-dimensional Fast Fourier Transform (FFT) processing, which provides range and Doppler resolution as well as Digital Beam Forming, providing a desired angular resolution. By adapting a radar system's radio frequency (RF) sweep, the number of antenna sub-arrays that are combined and the number of RF sweeps that are processed, it is possible to adapt the performance of the radar system to multiple requirements and applications.
A radar system typically includes a radar front end which in turn has means for generating a sweep signal and forming “chirp” signals that are transmitted, reflected and received by means of appropriate antennas provided in the radar system. The received signals, thus constituted by reflected radar echoes, are amplified and may be transferred in 16 similar channels to Analog Digital Converters (ADC:s); four channels for each ADC. The ADC:s are arranged to convert the received analog signals to digital signals which are transferred with four serial buses to two Digital Signal Processors, DSP:s.
All FFT processing and preliminary target identification are conducted in the two DSP:s, performing the FFT in parallel on all channels.
To prepare a raw target list, a first DSP, or Slave DSP, transfer preprocessed FFT data to a second DSP, or Master DSP, via for example Ethernet. The Master DSP then calculates and sends the raw target list to a Microcontroller Unit (MCU).
The MCU is arranged to perform an application that performs target identification and tracking. Additionally, other applications such as for example communications and system diagnostics are also performed in the MCU.
As evident from the above, there are a lot of components in a radar system according to the above, and there are thus many sources of error and malfunction.
When vehicle radar systems are concerned, there is a demand for a high level of performance; error and malfunction in such a radar system could lead to a falsified target list which in turn could lead to undesireable situations for the car driver. Today, the needed diagnostic coverage for such a radar system is normally not implemented due to system resources, costs and complexity, since additional monitoring hardware is needed.
There is thus a need for a vehicle radar system which is arranged for performing sufficient self-diagnostic procedures in a less complicated and more cost-effective manner than prior art vehicle radar systems, where such diagnostics have been present at all.